More than 250,000 vascular replacement devices are implanted every year in the United States alone. Most vascular prostheses are used to replace large internal diameter (over 6 mm) blood vessels such as in the aorta and major arteries, and currently available replacements are generally considered satisfactory. However, small internal diameter (less than 6 mm) vascular prostheses, such as those used for coronary arteries and peripheral vessels, suffer from low patency rates (they tend to be blocked). Recent efforts to develop suitable small diameter vascular prostheses have been hampered by an inability to find a material which promotes the development of a healthy neointima lining. If a proper surface is provided, such a lining is formed by the adsorption of proteins in the blood onto the surface followed by platelet and leukocyte adherence and fibrin polymerization, resulting in growth of a surface layer which includes a layer of endothelial cells in direct contact with the blood. If the luminal lining overdevelops, thrombus (bloodclots) can occur. If the lining does not adhere well to the inner surface of the prosthesis, embolization can occur where all or part of the neointima detaches and can become trapped in small blood vessels. The surface morphology, or surface topography, of the implant, has been shown to have a major effect on the adherence and development of the neointima lining.
Presently used techniques for forming the luminal surface of cardiovascular prostheses involves the use of woven or smooth synthetic materials. There is no control of uniformity in the blood contacting surfaces. A technique that allows for precise, tailor-made blood contacting surfaces would be of considerable value.